Field of the Invention
The present disclosure relates to a toner to be used for an image forming method, such as an electrophotographic method, and to an external additive for toner.
Description of the Related Art
An increase in speed, an increase in serviceable life, promotion of energy saving, and reduction in size have been further required for an electrophotographic image forming device, and in order to respond to those requirements, in view of the increase in speed and the promotion of energy saving, a further improvement in low-temperature fixability has been required for toner. In addition, in view of the reduction in size, in order to efficiently use a filled toner without any waste, a further improvement in transferability has been required. The reason for this is that when the transferability of toner is improved, the capacity of a residual toner container which recovers a residual transfer toner can be reduced.
From the points described above, in order to satisfy stable low-temperature fixability and transferability, various types of toners have been proposed.
Japanese Patent Laid-Open No. 2011-17913 has disclosed that when crystalline resin fine particles are externally added to toner particles, the low-temperature fixability can be improved. Japanese Patent No. 04136668 has disclosed that when fine particles of a crystalline polyester resin are provided on surfaces of toner particles, the low-temperature fixability and the durability can be improved. Japanese Patent Laid-Open No. 2013-83837 has disclosed that when crystalline resin fine particles having surfaces to which inorganic fine particles are adhered are adhered to surfaces of toner particles, the image density can be improved. Japanese Patent Laid-Open No. 2015-45859 has disclosed that when organic-inorganic composite fine particles in which inorganic fine particles are embedded in crystalline resin fine particles are externally added to surfaces of toner particles, the developability, the storage stability, and the low-temperature fixability can be improved.
According to the toners disclosed in the above documents, a certain effect on the low-temperature fixability of toner is confirmed. However, through intensive research carried by the present inventors, in consideration of the increase in speed, the increase in serviceable life, the promotion of energy saving, and the reduction in size, it was found that simultaneous satisfaction of the low-temperature fixability and the transferability is important and that the toners described above are still required to be further improved.